Sputter-deposited polycrystalline dielectrics generally have a preferentially oriented columnar crystalline habit (i.e. the tendency of the grains to form columnar crystals during deposition). Columnarity is generally aligned with the cathode bias of the sputtering tool. When the dielectrics are used to form tunable capacitors, and the like (and hence can have, for example, a perovskite structure, a pyrochlore structure, and the like), they are generally driven at a tuning bias of about 10% to about 40% of the hard breakdown voltage, which means that can they can be more susceptible to failure than non-tunable dielectrics, which are generally driven at 5% to 10% of the hard breakdown voltage. The biasing electric field of the capacitor is also generally aligned with the direction of columnarity. Hence, columnar crystalline habit will result in grain boundaries oriented from the lower to the top electrode and also aligned with the tuning electric field of the capacitor. Time dependent dielectric breakdown (TDDB) is the ageing of the capacitor under the bias and temperature. In TDDB processes, conductive dendrite growth causes the dielectric breakdown. The grain boundaries are the weak points of the polycrystalline film. In cases of grain boundaries aligned with the tuning electric field, conductive dendrites from the electrodes will quickly penetrate the crystalline structure leading to failure resulting in low mean time to failure (MTTF) of the devices. Furthermore, space-charge effects in the dielectric can limit the applications for capacitors using these dielectrics because of lack of control of the capacitance during product life under bias and losses in high frequency applications. While hillock suppression in the conductive electrode can be achieved by depositing a micro-crystalline sub-layer of dielectric, and/or a randomly oriented grain structure of dielectric, onto the conductive electrode prior to forming a columnar crystalline structure, the high frequency dissipation factor of such capacitors is high when the hillock suppression, and/or columnarity modification, is achieved by introducing the sub-layer as it results in an abrupt additional interface in the dielectric.